Lucanus cheni Huang

Huang, Hao, He, Yang & Shi, Zheng, 2011, Description of two new species of Lucanus Scopoli (Coleoptera: Scarabaeoidea: Lucanidae) from southeastern Tibet, China, Zootaxa 2987, pp. 56-64 : 56-59

Lucanus cheni Huang new species

Lucanus furcifer Arrow, 1950: 46 , partim [specimens from Sikkim (Lachen Lachung)], plate 3, Fig. 4; male from Sikkim; Didier & Séguy 1953: 30, Fig. 2 for male head, Fig. 6 for male “androcotype”; Bacchus 1978: 109, part of paralectotypes, 1 male from “Sikkim, Lachen Lochung, viii (MNHN, Paris)”; Huang 2006: 14, 18, Hanmi, Motuo, southeastern Tibet; Huang & Chen 2010: 156, figures for habitus, maxilla, labium and clypeolabrum of both sexes, male and female genitalia. (Taxonomic change according to the lectotype designation of Bacchus [1978]). Lucanus singularis: Lacroix, 1971: 566 , partim [“ paratype: 1 male, forme mineure, region thibetaine, Lacheng- Lachung”], Fig. 8 for male; Schenk, 2009: 7, Fig.1 [male from Sikkim], Fig. 2 [male from Bhutan] (misidentification).

Type material. Holotype ( Figs. 1 , 10): CHINA: Xizang (Tibet): 3, Linzhi Prefecture, Motuo County, Hanmi, 2150m, 17.VIII.2005, H. Huang leg.; deposited in the entomological collection of Shanghai Entomological Museum, Chinese Academy of Science, Shanghai, China. Paratypes: CHINA: Xizang: 23 3, 20 ƤƤ, Linzhi Prefecture, Motuo County, Hanmi, 2150m, 11–27.VIII. 2005, H. Huang, L. Tang & D.-K. Zhou leg.; 2 paratypes (1 3, 1 Ƥ) in Natural History Museum, London; 12 paratypes (6 3, 6 ƤƤ) in Hao Huang’s collection (Qingdao, China); 5 paratypes (2 3, 3 ƤƤ) in Chang-Chin Chen’s collection ( Tianjin, China); 8 paratypes (4 3, 4 ƤƤ) in the entomological collection of Shanghai Normal University, Shanghai, China; 16 paratypes (9 3, 7 ƤƤ) in Da- Kang Zhou’s collection (Beijing, China).

Holotype description. Body length measured from apex of mandible to terminal tip of elytra: 61 mm. Color and pubescence: Head, pronotum and elytra blackish brown, densely clad with yellow pubescence. Ventral surface of head, thorax and abdominal ventrites blackish brown, densely clad with yellow pubescence; pubescence on metasternum markedly longer than on other areas. All femora and tarsi on both dorsal and ventral surfaces blackish brown. All tibiae on both dorsal and ventral surfaces reddish brown.

Head: Frontal ridge clearly defined, more elevated in the middle. Lateral and posterior ridges evenly convex and rounded. Clypeolabrum (sensu Gravely 1915, Huang & Chen 2010) fused with frons, not defined by transverse suture, about 4 times as long as wide, with dorsal branch near apex; dorsal branch bifurcate at tip. Mandible about 3 times as long as head, strongly incurved at basal 1/3, with widely opened apical fork formed by apex and subapical ventral tooth; basal part swollen at the inner margin and serrate; the major inner tooth preceded by 4–6 smaller teeth in continuation to the base of the subapical tooth, and followed by 4–5 smaller teeth that are not continued to the base of the mandible. Antennal club with 4 antennomeres; antennomere 7 slender and sharply pointed at tip; antennomeres 8–10 lamellate. Maxilla with a long setose galea. Ligula bilobed, branches pointed at apex ( Fig. 21).

Legs: Protibia with 4–6 distinct teeth along lateral margin; apex bifurcate, acute. Mesotibia with 4–6 lateral spines in addition to terminal spurs and spines. Metatibia with three lateral spines in addition to terminal spurs and spines.

Male genitalia ( Fig. 4): Last abdominal tergite with ill-defined lateral angles. Last abdominal ventrite without apparent membranous area. Ventral plate of 9th abdominal segment with basal part almost even in width, and with thin longitudinal membranous stripe along the midline of the terminal expansion. Aedeagus in dorsal view about 2.30 times as long as wide. Basal piece in dorsal view rather oblong, nearly twice as long as parameres, with pair of sclerotized dorsal plates; ventral plate at caudal end of the basal piece membranous. Paramere with slender basal process. Penis about as long as parameres, with flagellum (permanently everted internal sac) about 5 times as long as parameres.

Male paratypes. Body length measured from apex of mandible to terminal tip of elytra: 42–81 mm.

Variation. Apical fork of the mandible widely opened in large-sized males, narrowly opened in medium-sized males, absent in small-sized males. Clypeolabrum longer in large-sized males, shorter in medium-sized males, with upper branch not bifurcate at apex in small-sized males. Number of inner teeth on the mandibles varying with specimen size. Frontal ridge of head in small-sized males not elevated medially. Lateral ridges of head in small-sized males not convex laterally or posteriorly.

Female paratypes ( Fig. 2 ). Body length measured from apex of mandible to terminal tip of elytra: 28–41 mm.

Color and pubescence: All structures except the tibiae black or blackish brown on both dorsal and ventral surfaces. Tibiae varying from entirely black to entirely reddish brown among individuals. Dorsal surface of body entirely glabrous, only sparsely clad with short yellow pubescence along lateral elytral margins in fresh specimens. Ventral surface of body with dense, yellow pubescence.

Head: Canthus with both anterior and posterior angles clearly defined; anterior angle outside of eye and about as far as the posterior angle; lateral margin straight. Frontal and lateral ridges obsolete, not defined. Clypeolabrum in dorsal view transverse, flat at tip, not protruding forwards medially. Both left and right mandibles with clear dorsal tooth, 2 widely-separated inner teeth and large gap behind apex; lateral margin between 2 inner teeth concave and long.

Pronotum: About twice as wide as long, widest behind middle; anterior angle produced; lateral angle clearly defined, pointed; posterior angle obtuse; lateral margin before lateral angle evenly convex.

Female genitalia ( Fig. 5): Last abdominal tergite with poorly-defined lateral angles. Last abdominal ventrite with large membranous area medially. Hemisternite with outer apex protruding beyond inner apex; the inner lateral margin of sclerotized part short. Spermatheca sclerotized and J-shaped. Spermathecal duct about 2–3 times as long as spermatheca. Spermathecal gland slightly longer than spermatheca. Central conjunction of 9th tergites broad at tip.

Type locality. China, southeastern Tibet, Motuo.

Etymology. This species is dedicated to Mr. Chang-Chin Chen ( Tianjin, China), a collaborator and good friend of the senior author.

Remarks. This new species is similar to Lucanus thibetanus , but it can be distinguished using the following characters: male mandible with greater number of inner teeth behind the major inner tooth; lateral and posterior ridges of the male head more convex laterally and less convex posteriorly; female clypeolabrum shorter and narrower, with the lateral corners of the clypeus indistinct; anterior angle of the female head usually indistinct; apical fork of the female protibia markedly shorter; size of the aedeagus smaller, with the apical part of the penis concave at the outer lateral margin (the male genitalia of all known subspecies of Lucanus thibetanus have been examined); spermathecal duct of female genitalia shorter (all subspecies of Lucanus thibetanus except L. thibetanus isaki Nagai, 2000 from northern Myanmar have been examined); hemisternite of the female genitalia markedly smaller.

This new species can be easily distinguished from the unique female holotype of Lucanus singularis Planet, 1900 by the following characters: clypeolabrum not protruding medially, canthus with the anterior angle clearly defined and outside of the eye. A series of specimens identified as Lucanus singularis were recently discovered from the Chayu area, southeastern Tibet, which match the most characters of the holotype of Lucanus singularis . The male of Lucanus singularis (sensu Huang & Chen 2010) has many differences compared to the male of Lucanus cheni , such as a much shorter and less dentate mandible.

This new species had been identified as Lucanus furcifer until the senior author noticed that Bacchus (1978) published a lectotype designation of Lucanus furcifer and selected a male specimen of Lucanus thibetanus from Yunnan as the lectotype of Lucanus furcifer . As fully discussed in the recent publication ( Huang & Chen 2010), Arrow (1950) made the mistake of mixing two species into one taxon: a Sikkim species represented by the figures of the males in Arrow (1950: plate 3, Fig. 4) and Didier & Séguy (1953: Figs. 2 , 6 ), and a subspecies of Lucanus thibetanus from Yunnan represented by the figures of the males and females in Planet (1903: Figs. 1, 2 ) and Didier & Séguy (1953: Figs. 3, 5, 7 ). Since Bacchus (1978) selected a male specimen from Yunnan as the lectotype of Lucanus furcifer , the Sikkim species is an unnamed species, and Lucanus furcifer now refers to a subspecies of Lucanus thibetanus . The lectotype of Lucanus furcifer ( Fig. 3) matches all the diagnostic characters of Lucanus thibetanus pseudosingularis Didier & Séguy, 1953 , therefore it is a senior synonym of the latter. For the species delimitation of Lucanus thibetanus , see Huang & Chen (2010). The taxonomic changes of Lucanus thibetanus furcifer in the literature are stated below.

Figures

FIGURES 1 – 2. Lucanus cheni habitus in dorsal view. 1 — male holotype; 2 — female paratype.

FIGURES 6 – 9. Lucanus langi habitus in dorsal view. 6 — male holotype; 7, 8 — male paratypes; 9 — female paratype. FIGURES 10 – 13. Male head in dorsal or anterodorsal view to show clypeolabrum and details of mandibles. 10 — Lucanus cheni holotype; 11 — Lucanus langi paratype; 12 — Lucanus langi paratype (same specimen as in Fig. 8); 13 — Lucanus smithii (Kurseong, India, photo by A. Galant). Abbreviations: s, basal part of mandible swollen and serrate on inner margin; b, clypeolabrum bifurcate at tip; nb, clypeolabrum non-bifurcate; ns, basal part of mandible non-serrate and not swollen. FIGURES 14 – 15. Lucanus langi, part of habitus in ventral view. 14 — male paratype (same specimen as in Fig. 7); 15 — female paratype (same specimen as in Fig. 9).